Busses will depart from Tronchetto near Piazzale Roma.
The departures are not daily but up to several times a week.
The Eurolines pass is a good deal if you want to visit more cities in Europe.
There are more than 500 destinations through whole Europe including Greece, Marocco and Turkey.
Prague, Budapest, Vienna are easy to reach from Venice.
A youth pass for 15 days in the high season cost €290 and €345 for adults.